Balers for forming large parallelepiped bales are often equipped with a pre-compression chamber in the form of a curved chute or duct in which crop material is accumulated until it reaches a predetermined density whereupon a stuffer arrangement is actuated to lift the charge of crop material into the baling chamber at a location just behind the baler plunger. Once the charge of crop material is in the baling chamber, the plunger operates to compact the charge against previously compacted crop material located in the baling chamber and acting against the restriction of adjustable side panels which adjust the cross section of the baler to restrict the movement of the crop material so as to cause a bale having a desired density to be formed. In order to ensure that the formed bale is of a uniform density, it is a known practice to measure the force required to compact the crop material, this force being indicative of the density. Because the density of the charge of crop material placed in the baling chamber may differ from side-to-side, it is known to take force measurements in each of a pair of laterally spaced connecting rods extending between the plunger driver and the plunger. A signal is generated using these measurements to notify an operator of the need to cause the baler to be displaced transversely one way or the other relative to a crop material windrow in order to cause additional crop material to enter the baler on that side which has the lower measurement of compaction force.
U.S. Pat. No. 4,627,341, dated 9 Dec. 1986, and U.S. Pat. No. 5,253,570, dated 19 Oct. 1993, disclose respective examples of load sensors incorporated in transversely spaced connecting rods of the baler plunger drive for the purpose of measuring the load imposed on a bale being formed and generating signals used in a control system for aiding an operator in forming uniform density bales. These load sensing devices are located so as to be at a central horizontal plane through the connecting means when the plunger is fully-extended to the rear during compaction of the charge of crop.
Large square balers of different sizes experience plunger loads proportional to the lateral cross-sectional area contained between the opposite side walls of the baling chamber or bale case. Data resolution is lost if a more robust load pin is used than is required for the loads that occur. Consequently, a manufacturer that makes various sizes of balers is required to keep an inventory of load pins of various sizes, which increases cost.